La'An Noonien-Singh recognizes a Gorn trap as the Enterprise is attacked near a brown dwarf, and the crew must outwit the Gorn ships.
While delivering supplies to a Federation colony, the Enterprise finds most of the colonists dead. Security chief La'An Noonien-Singh, the sole survivor of a Gorn attack in her childhood, recognizes the tactics of a Gorn hunt. A Gorn ship badly damages the Enterprise, and with equipment failing, M'Benga and Chapel care for the wounded using older methods.
The crew draws the attacker into the atmosphere of a brown dwarf, where sensors and shields are useless. Spock mind-melds with La'An to learn how the Gorn communicate, then tricks one Gorn ship into firing on another. The Enterprise ejects the unstable nuclear-powered air filter it had been delivering, and the explosion convinces the last Gorn ship that it has been destroyed.